中文摘要:查岗诺尔铁矿区位于西天山伊犁地块东北缘博罗科努山系的主脊线上,属中天山北缘活动陆缘带。该矿区位于破火山口的西北缘,矿体产状受火山穹窿构造的制约。赋矿围岩为下石炭统大哈拉军山组安山岩及安山质火山碎屑岩。该矿床的成矿期可划分为矿浆期和热液期,隐爆作用伴随成矿全过程。矿浆成矿期形成了浮渣状、斑点状、致密块状、贯入角砾岩状和阴影状等矿石;热液成矿期形成了对称条带状、复角砾状及网脉状等矿石。矿石的稀土元素球粒陨石标准化配分曲线均属向右倾的轻稀土元素富集型,微量元素表现出特征的Nb、Ta亏损和大离子亲石元素富集。矿石的稀土元素和微量元素总体特征与安山岩一致。矿石和安山岩的Pb同位素数据在Pb同位素比值图上共线。安山质火山岩中普遍含有数量不等的磁铁矿。这些特征都表明了矿石与安山岩的亲和性。矿石的氧同位素组成与典型的岩浆型矿床相一致。该矿床属以安山质岩浆为母岩浆的岩浆矿床(主要)和热液矿床(次要)的复合型矿床。
Abstract:The Chagannur iron ore district is located in the Boluohonu Mountain situated in northeast Ili Block in western Tianshan, belonging to the active continental margin on the northern side of the Middle Tianshan Plate. The iron deposit lies on the northwest fringe of the volcanic crater, and the attitude of the ore body is restricted by the volcanic dome structure. Wall rocks, mainly consisting of andesite and andesitic volcaniclastic rock, belong to Dahalajunshan Formation. The formation of the ore deposit can be divided into magmatic ore-forming period and hydrothermal metallogenic period, with the former being dominant. Cryptoexplosion occurred during the whole metallogenic period. Some kinds of ores were formed during the magmatic ore-forming period, such as scum ore, spotted ore, massive ore, injection and breccia ore and shadow ore. Lots of ores were formed in the hydrothermal metallogenic period, such as symmetrical banding ore, multi-breccia ore and network ore. The REE distribution patterns of the samples are similar to each other, showing obvious enrichment of light REE (LREE) and large ion lithophile elements (LILE) and evident depletion of Nb and Ta in the primitive mantle normalized spider diagrams. Ores and andesite have similar REE fractionation patterns and trace element fractionation patterns. Pb isotopic ratios of ores and andesite show linear correlation in the Pb isotopic ratio graph, and there are varying amounts of magnetite in andesitic volcanic rocks. These characteristics suggest affinity between ores and volcanic rocks. Oxygen isotopic data range of ores is consistent with the variation range of typical magmatic deposits. Hence, this iron deposit is mainly of polygenetic magmatic type and subordinately of hydrothermal type in genesis, with the andesitic magma as the primary magma.
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基金项目:本文得到中央高校基本科研业务费专项资金(编号:CHD2010JC089)、长安大学基础研究支持计划专项基金和中国地质调查局项目“西天山阿吾拉勒成矿带铁矿成矿条件、成矿规律与勘查示范研究(编号:资[2010]矿评01-03-26)”的联合资助
引用文本:
汪帮耀,胡秀军,王江涛,邵青红,凌锦兰,郭娜欣,赵彦锋,夏昭德,姜常义.2011.西天山查岗诺尔铁矿矿床地质特征及矿床成因研究[J].矿床地质,30(3):385~402汪帮耀,胡秀军,王江涛,邵青红,凌锦兰,郭娜欣,赵彦锋,夏昭德,姜常义.2011.Geological characteristics and genesis of Chagannur iron deposit in Western Tianshan, Xinjiang[J].Mineral Deposits30(3):385~402
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